சுடர் விழி

தூறிய மழைத் துளி தூரமாய் போனதே
சுட்டும் உன் சுடர் விழி எனை சுடாமல் சென்றதே...

Machine and Instrument

Machine and Instrument

      What is a machine and what is an instrument? Both are same? If yes, why are two names? 

      Machine is a device(....?) which reduces human effort in doing something (any work of any kind.... constructing, destructing, modifying, arranging....). Machine directs and controls the energy; this energy may or may not be produced by the same machine.

      On the other hand, instrument is a tool which is part of a machine. Instrument does the sensing and measuring operations. 

      For example, speedometer is an instrument which measures the speed. This speedometer is part of a vehicle which is a machine.

      By size wise, the bigger is machine and the smaller is instrument. This could be understood by the nature's philosophy; anything is flowing from higher side to lower side.... Energy is propagating from something to nothing. So, the bigger machine produces the energy and it is used for its functionality. 

      This is what we discussed in the class. But, please look at the following picture for dictionary meaning of Machine.

         

You please read the above passage and say your views on "Machine and Instrument".

some related links on P&ID.........

for information on P&I Diagram and calibration :
http://iamechatronics.com/notes/general-engineering/231-instrumentation-documents-loop-diagrams

for information on datasheets of calibration procedure:
http://www.standard.no/pagefiles/1239/i-001r2.pdf

for information on functions of instruments and control components, etc.,
http://www.instrumentationtoolbox.com/2011/01/piping-and-instrumentation-diagrams-p-4.html#axzz3pf6nPxUT

Calibration

Today I bought an Ironbox; Philips make, 1100 watts.

There's a knob to adjust temperature for specific type of cloth materials....wool, linen, cotton, silk, etc., At home, I started pressing my dresses with different temperature levels.

A doubt arised that how could I know the temperature of that level which the knob indicates. That is, if I position the knob in "Cotton", the ironbox will function at the temperature for the cotton material. But, is that temperature what actually set for that level? How do I know? Even if I suppose to believe the manufacturer during the initial days of my purchase, would it (the temp level) not be changed on later days?

How could I check that the ironbox is working at the required temperature level what I require? And, how much it deviates from the actual temperature level?

Any procedures available to check it?

Is this the commercial testing and calibration? If yes, which part of the ironbox to be tested and which part to be calibrated.....with which standard?

http://www.ni.com/pdf/testsummit/us/Calibration.pdf
http://www.qualitymag.com/articles/88760-management--calibration-can-be-risky-business
http://www.capterra.com/calibration-management-software/
https://www.gemeasurement.com/sites/gemc.dev/files/4sight_datasheet_english_0.pdf
http://www.bis.org.in/lab/labs.htm
http://www.bis.org.in/org/AnnualReport0708.pdf
http://www.encyclopedia.com/topic/National_Bureau_of_Standards.aspx

Test Procedure Design

Responsibility of test measurement professional - to design a test procedure

why to design a procedure for testing? - can't make the test just like that - testing, often, costly  - to design, assemble, instrument and conduct. mostly, v'll get only one chance to take measurement. so before conducting test, it's necessary to design a procedure where the Professional's knowledge / input is essential.

To design a test procedure, the following teams need to be involved. 

               1. Design engineering

               2. management

               3.quality assurance

               4.test rig designers

               5.test measurement professionals

               6.test operators

Test Objective:

           is a written statement - describes the purpose of the test - background information why the test is being carried out, the range of test conditions, format of the expected test results.

            If we take a microwave oven as an example to be tested (temperature) - the statement should specify the purpose of test that 

       temp can't be raised or lowered to the required level in the prescribed time

       the temp developed in the system is wrong that the process variable is different from the set point

       the oven's temp may be in wide range; it's better to fix the range of temp in which the test is to be        conducted

       How the test result should be given for the further process.

             

Testing and Calibration of Instruments

Test Measurement Instrumentation :

           Measurement is fulfilled only when you are able to express the results in numbers (understandable way) - if you measure the quantity of milk in a cup, you should be able to say it as 250 ml / 500 ml / 50 ml.....of milk is in the cup. If you say there is "கொஞ்சம் பால்", then you have not performed the measurement there.

           Measurement involves two things : Measuring unit (Test Object - is an unit / device which is used to test the object (to be measured)) and the object (parameter / physical object...)

           The performance of the Measuring unit (Test object) is expected to be same for different conditions of and to perform correctly under specified conditions.

           Measurement system involves the following.

                        1. Components.

                        2. Installation

                        3. Wiring

                        4. Calibration 

Measurement Instrumentation and Test Measurement Instrumentation :

                If the result of the measurement system is used for explaining / knowing the condition of the environment / process then that is known as Measurement Instrumentation.

               If the result of the measurement system is used to verify whether the product is working against the specification and to monitor the operation of equipment (operation means not only checking whether it is working or not, but also working under different relevant conditions), then that is known as Test Measurement Instrumentation.

                 R&D labs

                 Product development / design centres

                 Manufacturing plants

                 Maintenance facilities

                 Commercial and Household products - are the places where the test measurement instrumentation is used.

Components of Test Measurement (TM) System:

                        Sensor / Transducer (Input)

                        Signal conditioning system (Conditioning and Transmission)

                        Display, Data logger, Data Acquisition system, Data Analyzer (Output)

Characteristics of an ideal TM System:

           Even though it's a whole system of individual components, the performance of the system is based mostly on the character of the transducer / sensor. Because, this component only has direct contact with the process / environment of the process. 

            * small size and low mass

            * immune to environmental changes

            * wide range of operation (reduces the no. of sensors to be installed - reduces the space)

            * high accuracy (reduces the measurement uncertainity)

            * good linearity (improves rangeability and accuracy)

            * wide frequency response

            * low cost

            * ruggedness

            * ease of operation

Invasive and Non invasive measurement system (contact and non-contact transducers /sensors with process or test system)

Test Measurement Instrumentation and Process Instrumentation - for laboratory purpose and Field purpose respectively - in general

         these are distinguished by

                       the place of use (lab or industry)

                       the size (small or heavy)

                       the application (specific or wide range)

                       the frequency response (high or static to low)

                       stability (less or more)

                       ruggedness (less or more)

                       accuracy (high or low)

                       price (high or low)

                       environmental range (wide or limited)

                       use of signal conditioning unit (separate unit or self contained)

                       sensor as transducer or sensor as transmitter.

எலக்ட்ரோக்குறள்

1. ஏசி மாறுமே டிசியாய்  ஈசியாய்
   ரெக்டிபயர் வழி  செல்லின்
2. சென்டர்டேப் பிரிட்ஜ் புல்வேவ் வகையாம்
    ஹால்ப்வேவ் ரெக்டிபையர் மற்றொன்றாம்
3. ஃபில்டர் உள்செல்லும் பல்சேட்டிங் டிசி
    வெளி யாகும் யுனிடைரக்சனலாய்
4.  ஃபார்வர்டில் உள் செல்லும் கரண்ட்
     ரிவர்சில் டையோடால் தடுக்கப்படும்